The Manhattan Project was a top-secret research and development project that produced the world's first atomic bomb during World War II. Led by the United States and its allies, the project involved many of the world's best physicists, billions of dollars of funding, and 125,000 manufacturing plant workers who knew nothing about what they were working on. The weapon was instrumental in ending the Second World War, but it sparked an arms race between the Soviet Union and the United States to achieve nuclear supremecy that lasted until 1991. The following documents discuss the results of the first nuclear weapons test, how the bombs were assembled, and the scientists who worked on the project.